Doctrine Of Equivalents: An Approach To Analyse Patent Infringement

Introduction

The advancement of new technologies throughout time has led to an unprecedented increase in patent-related conflicts. A patent is granted by a patent office, which is a monopoly right for a novel, useful, and non-obvious innovation. A patent holder has the right to prevent others from using their invention, and they are entitled to reasonable returns on their efforts and investment.

Patent Infringement

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Any person who exercises the exclusive rights of the patent holder without consent/licence of the patent owner is liable for infringement. Sections 104-114 of Indian Patent Act, 1970 contains regulations regarding patent infringement. There are two types of patent infringement: (1) literal infringement and (2) infringement under the Doctrine of Equivalents. A literal infringement occurs when a patentee shows that the infringing product/procedure corresponds to every element of the patent’s claim and is commercially marketed without the patentee’s consent.

The Doctrine of Equivalences depends on two tests

  1. “All Elements” Test
  • According to “All Elements” test, the Doctrine of Equivalents must be applied to each individual claim element and not to the claimed invention as a whole.
  • It is essential to show that every element of patented invention, or a substantially similar component, is present in the allegedly infringing product or process.
  • The new invention must have substantial equivalents of the previous invention’s components. They must therefore conform to the standards of triple identity test.
  • Applying the aforementioned test requires fulfilling a crucial requirement that equivalency should be taken into account once a claim has been filed and not after the grant of patent.
  1. Triple Identity Test
  • The triple identity test serves as the foundation for Doctrine of Equivalents.
  • If the allegedly infringing product/process deviates from the literal language of the claims and performs the same function in the same manner to achieve the same outcome as the claimed product/process, infringement can be proved by the application of Doctrine of Equivalents.
  • When determining the substantiality of the variations, following considerations should be made:
  1. If a person with expertise in the field could have known such an equivalent.
  2. Whether the accused individual intentionally copied or was trying to design around it but ended up getting the same results.
  3. If the persons skilled in the art are aware that the accused and claimed innovations are equivalent.

The Indian courts have made multiple attempts to adopt and apply the Doctrine of Equivalents in India, following the lead of US judgements. This doctrine was recently applied in the case of FMC Corporation & Ors. vs Natco Pharma Limited (19 September, 2022).

Brief Facts

  • Indian Patent No. 298645 (suit patent/IN’645), entitled “Method for Preparing N-Phenylpyrazole-1-Carboxamide,” was granted to FMC Corporation and FMC Agro Singapore Pte. Ltd on 12.2005. The expiry of Patent No.IN’645 is on 06.12.2025.
  • The Plaintiff, FMC Corporation sued Natco Pharma Limited (Defendant), claiming that Defendant’s method of synthesizing an anthranilic diamide insecticide called Chlorantraniliprole (CTPR) infringed on Plaintiffs’ patented method.
  • The reactants in the Plaintiff’s patented method area carboxylic acid of Formula 2, an aniline compound of Formula 3, and sulfonyl chloride whereas reactants in the Defendant’s process included a carboxylic acid of Formula 2, an aniline compound of Formula 3, and thionyl chloride.
  • After receiving  summons on May 23, 2022, the defendant asserted two things:-
  1. They would market their CTPR product upon the expiration of two prior product patents (IN 201307 (IN’307) and IN 21332 (IN’332)) covering CTPR, both of which would end on August 13, 2022.
  2. Their production process didn’t breach Plaintiffs’ patent IN’645.
  • Two Scientific Advisors named Gopakumar G. Nair and Prof. Bhalchandra Bhanage were chosen to inspect both the patented process of the Plaintiff’s and the Defendant’s on July 29, 2022.

Issues

Does the Defendant’s method of producing CTPR violate the Plaintiff’s patented method under ‘Doctrine of Equivalents’?

Case Analysis

The court considered the following in evaluating whether Defendant’s procedure was substantial equivalent to the Plaintiffs’ procedure:

  1. The order of steps in which the Plaintiffs’ and Defendant’s processes took place.
Plaintiff’s Patented Process Defendant’s Process
STEP 1:

Mixing the carboxylic acid with the aniline compound to obtain a mixture.

STEP 1:

Mixing the carboxylic acid with thionyl chloride to obtain acid chloride

STEP2:

Combining the mixture obtained in step1 with sulfonyl chloride to obtain CTPR.

STEP 2:

Combining acid chloride with an aniline compound to obtain CTPR.

  • The court noted that there were differences between the sequences of steps as well as in the intermediates formed during the Plaintiff’s process and the Defendant’s process.
  1. Is thionyl chloride a substitute for sulfonyl chloride provided sulfonyl chloride was an essential component.
SULFONYL CHLORIDE THIONYL CHLORIDE
The Plaintiff’s patented process included sulfonyl chloride, an organic chloride. The defendant used thionyl chloride,an inorganic chloride.
The role of sulfonyl chloride is of a coupling agent. The role of thionyl chloride is of a chlorinating agent.
The use of sulfonyl chloride resulted in the formation of a solid toxic by-product of methane sulfonic acid. The use of thionyl chloride resulted in formation of SO2 and HCl in gaseous form.
  • Due to above-mentioned factors, both scientific advisors determined that sulfonyl chloride was an essential element and thionyl chloride was distinct from sulfonyl chloride. Hence, it wasn’t a substitute for the latter.

Judgement

The single-judge bench upheld the principle of ‘Doctrine of Equivalents’ pointing out that there is no infringement because the reagent, sulfonyl chloride, is an essential element of Plaintiffs’ process, whereas Defendant’s process admits to using thionyl chloride as the reagent, which plays a distinct role in carrying out the same task and nearly getting same result. Therefore, the court ruled out that the Plaintiffs’ process wasn’t infringed by Defendant’s process.

CONCLUSION:-

  • Although the Doctrine of Equivalents has been evolved in foreign jurisdictions for more than a century, Indian jurisprudence is yet to formulate a non-ambiguous and clear position on the subject.
  • There are a lot of discrepancies and uncertainties among the general public as a result of doctrine’s lack of precise and linguistic definition in the Indian context.
  • However, considering rapidly developing technology, the judiciary is anticipated to deal with numerous cases in the upcoming year. Therefore, it is of utmost importance to develop a legislative framework for the same in both the Indian and global contexts.

Author: : Nirali Chheda  is a 2nd yr LLB Student at Kishinchand Chellaram Law College, Mumbai, in case of any queries please contact/write back to us via email to chhavi@khuranaandkhurana.com or at Khurana & Khurana, Advocates and IP Attorney.

 REFERENCES:-

  • Fmc Corporation & Ors. vs Natco Pharma Limited, https://indiankanoon.org/doc/51656490/
  • Singh and Associates, Patent infringement and the Doctrine of Equivalents, Mondaq, https://www.mondaq.com/india/patent/898674/doctrine-of-equivalents-patent-infringement
  • Preetesh Aggarwal, Understanding the Doctrine of Equivalent patents, iPleaders, https://blog.ipleaders.in/understanding-doctrine-equivalent-patents/). 
  • Doctrine of Equivalents and prior history estoppel https://www.legalserviceindia.com/legal/article-4-doctrine-of-equivalents-and-prior-history-estoppel.html
  • https://lawbeat.in/news-updates/delhi-high-court-gives-nod-natco-pharma-introduce-ctpr-insecticides-its-formulations

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